Treatment of lubricating oils



Patented Aug. 20,-1940 PATENT OFFICE 2,211,944 TREATMENT OF LUBRICATI'NG OILS Chester E. Andrews, Overbrook, and Merrell B. Fenske, State College, Pa., assig'nors to R6hm & Haas Company, Philadelphia, Pa.

No Drawing. Application June 3, 1938,

Serial No. 211,566

4 Claims.

This invention relates to a method for converting high boiling, very viscous lubricating oils into lubricating oils having a much lower viscosity and a viscosity index which is approxi- 5 matelythe same as that of the original oil;

In refining petroleum there is usually a large fraction of heavy, very viscous oil obtained for which there is no very great demand, Some of this oil finds use as a lubricant in the cylinders lo of steam engines but it is not suitable for other types of lubrication, and is particularly unsuited for use in internal combustion engines of the automotive type. For lubricating internal combustion engines it is desirable to use an oil with 35 a high viscosity index but having a much lower viscosity than the heavy oils used for lubricating steam engine cylinders. It is possible by distillation of the very viscous oil to obtain only a small amount of the so called neutral oil having the so low viscosity and high viscosity index desired.

The object of the present invention is to provide a method whereby a considerable fraction of the highly viscous oil canbe converted into an oil which has a much lower viscosity but 5 approximately the same viscosity index as the original oil. g This object is accomplished by heating the oil, methanol and, if desired, some water to a high temperature in the presence of a hydrogenating catalyst and under superatmospheric pressure. By this treatment the heavy oil is broken down to products of much lower viscosity and approximately the same viscosity index.

It is well known that by heating these highly $5 viscous oils to temperatures of 350 C. and higher they can be cracked into products of lower molecular weight, such as gases, gasolene fractions, kerosene and high fractions. The higher fractions, however, yield oils of the lubricating type which have a much lower viscosity index than that of the original oil. In many cases the cracking operation converts practically all of the heavy oil to low boiling fractions which contain no lubricating oils whatever. For example, if Pennsylvania Bright Stock is heated to about 380 0.,

it is entirely converted into gas, gasolene, keroseneand gas oil; no lubricating oil whatever remains. However, if there is some methanol or a mixture of methanol and water present along with a suitable catalyst, a large portion of the very viscous oil is converted to a lubricating oil of high viscosity index but of much lower viscosity than the original oil. At the same time 5 the percentage of the lower boiling fractions is considerably less than when no methanol and catalyst are present.

The catalyst used may be any or the usual reducing catalysts such asmetalllc nickel or one composed of the oxides of a hydrogenating metal 5' and an. acid-forming metal. The latter type may be, for example, copper-chromium oxides; copper, chromium, barium oxides; manganese, zinc, chromium oxides etc. Catalysts containing the oxides of copper, chromium and barium have lib been found to be very eflectiv e.

The temperature may vary within fairly wide limits but is more or less determined by the nature of the oil and the ease with which it decomposes. With a Pennsylvania Bright Stock, In for example, temperatures of 300 to 400 0. give good results. At the higher temperatures there is a decided tendency for low boiling products to be formed whereas at the lower temperatures there usually is a large amount of heavy, highly viscous oil left after the neutral oil has been distilled from the reaction product.

The amount of methanol employed can also be varied within fairly wide limits. Good results have been obtained when the weight of methanol varied from about 8 to about 40% of the weight of the oil. The water present, if any, may be as much as 25% or more of the weight of the oil.

The pressure may vary from about 250 to 2000 pounds or more per square inch. The actual pressure can be adjusted by varying the term perature. At the lower temperaturesthe pressure will usually be lower because it is generated by the decomposition of the oil and methanol and there is less decomposition at these temperatures. Low pressures may also be maintained at the higher temperatures by suitably releasing some of the gas generated.

The process may be carried out continuously in a suitable apparatus or in individual batches; 40 In the former case a mixture of the oil and the methanol or methanol and water may be flowed continuously over the catalyst at the desired temperature. For batch operations the alcohol or methanol and water may be forced into a re- 5 action chamber filled with the oil and catalyst and allowed to bubble through, or a mixture of all the ingredients may be placed in a shaking bomb and agitated for a time sufllclent to bring about the desired change.

The results obtained by this method of treating very viscous lubricating oils may be seen from the following table. These results were obtained by heating g. of Pennsylvania Bright Stock with 10 g. of catalyst consisting of copper, chro- 5s mium and barium oxides, and the indicated amount of methanol or methanol and water for four hours at the temperature shown. The pressure given in the fiith column is that which developed in the bomb due to decomposition and vaporization of the materials. The percentage of neutral oil obtained is given in the sixth column, the last figure in the column being the amount of neutral oil distilled under 10 mm. pressure directly from the original oil. The seventh column gives the viscosity index of theneutral oil as calculated from the Saybolt viscosities at 100 and 210 F. The eighth and ninth columns show the amount oi light oil and heavy residue obtained from the treated oil by distillation. -The distillation was carried out as follows: At atmospheric pressure up to 201' C Gasoline fraction At atmospheric pressure 202 to 289' (3-- Kerosene At 10 mm. mercury column up to 248 C Gas oil At 10 mm. mercury column 247 to Neutral At 10 mm, mercury column above 348' c Bottoms The amount of neutral oil in the original viscous oil was determined by the same method our co-pending application, Serial No. 155,856

filed November 30, 1934.

We claim:

' 1. The process or converting lubricating oils of high viscosity and high viscosity index to lubrieating oils of lowerviscosity and substantially the same viscosity index, which comprises heating a mixture consisting essentially of the high viscosity oil and methanol at a temperature of from about 300 to about 400 C. under a pressure of from about 250 to about 2000 pounds per square inch in the presence of a reducing catalyst.

2. The process oi converting lubricating oils of high viscosity and high viscosity index to lubrieating oils of lower viscosity and substantially the same viscosity index,'which comprises heating a mixture consisting essentially of the high viscosity oil and methanol at a temperature of from about 300 to about 400 C. under a pressure of from about 250 to about 2000 pounds per square inch in the presence of a catalyst consisting essentially of the oxides of copper, chromium and barium.

3. The process of converting lubricating oils of or distillation. high viscosity and high viscosity index to lubri- G. G Pounds Percent Percent Percent Run No. C. neutral V. I. lighter heavier (H10H H40 pressure on am ass 50 0 also 2s 0a 5a 18 ass 0 s90 14 7s 1a a ass so o 1,045 21 9e 4 10 ass 10 o 270 so a 70 sec 50 as 2,000 20 so so as 380 1 10 10 000 as 102 2s s25 as 1,400 is s7 4 12 a ass 0 o 000 o a0 12 Original oil distilled 15 97 so The eflect of the methanol or of the mixture of methanol and water can be seen by comparing the figures for Run No. 8 where no methanol was present with the other runs. When no methanol is present, the oilissimply cracked into the lighter hydrocarbons, no neutral oil being formed. When methanol is present, a large percentage of the heavy. highly viscous oil is converted into a desirable lubricating oil of high viscosity index.

The presence of water has a beneficial eiIect on the reactions, particularly at the higher temperatures, which results in higher yields and better viscosity index than are'obtained when no water is present.

The foregoing table has'been given as illustrative of the results which can be obtained. The

--process may, however, be applied to other oils of Pennsylvania or other origin 'with beneficial results.-

This application is a continuation-in-part of eating oils of lower viscosity and substantially the same viscosity index, which comprises heating a mixture consisting essentially of the high viscosity oil, methanol and water at a temperature of from about 300 to about 400 C. under a pressure of from about 250 to about 2000 pounds per square inch in the presence of a reducing catalyst.

4. Theprocess of converting lubricating oils of high viscosity and high viscosity index to lubricating oils of lower viscosity and substantially the .same viscosity index, which comprises heating a mixture consisting essentially of the high viscosity oil, methanol and water at a temperature or from about 300 toabout 400 C. under a pressure of from about 250 to about 2000 pounds per square inch in the presence of a catalyst consisting essentially of the oxides of copper, chromium and barium.

CHESTER E. ANDREWS.

MERREIL R. FENBKE. 

